Transcript Multi-test strategies for the determination of HIV

Multi-test strategies for the
determination of HIV
serostatus without the use
of Western immunoblotting
New strategies for HIV diagnostic
algorithms
Jane Feldman, Susan Wells, Michele Owen, and
Tim Granade
Current HIV testing algorithm
CDC/APHL -- 1993
Screen by EIA
 Re-test reactive specimens in duplicate
using same EIA
 Specimens reactive in at least 2 of 3 tests
are further tested by WB/IFA

Changes in HIV diagnostic testing
Introduction of 3rd and 4th generation HIV
EIAs
 FDA approval of rapid HIV antibody
screening tests
 Use of HIV nucleic acid detection assays

Can alternative strategies provide
equivalent or better results?
Methods

Samples (n=342) that were submitted to
the CDC HIV CLIA Reference Laboratory
– “Difficult” samples
 Most submitted due to inability of public health
labs to reach a definitive answer
 Suspicion of HIV-2
– Many likely screened with Bio-Rad HIV1/2
plus O
HIV diagnostic testing strategy

Standard algorithm (reference)
– Biorad 1/2/O EIA / WB Biorad or Maxim

Additional testing
– Abbott rDNA HIV-1/2
– Multi-spot HIV-1/2

Algorithms analyzed
– Dual EIA
– EIA/RT
– Triple tests

Specimens
– N=342
Proposed Testing Strategies for Laboratory
HIV Testing Facilities
A1 EIA (HIV-1)
Strategy 1. HIV-1 EIA/WB/NAAT
A1
(+)
A1 (-)
Repeat A1 (in duplicate)
A1 (++ or - +)
Negative for
HIV-1
antibodies†
B2 Individual HIV-1 NAAT
A1 (- )
(option for initial plasma submissions)
OR
B1 HIV-1 WB or HIV-1
IFA
Positive
Positive for
HIV-1
antibodies
Negative
Negative for
HIV-1
antibodies†
Negative*
Indeterminate
Inconclusive for HIV-1
antibodies; request redraw
in 2-4 weeks; requires
medical follow-up for
further evaluation and
testing †∞
Positive**
Positive for
HIV-1
antibodies
and HIV-1
RNA
* HIV-1 RNA not detected, however, a WB or IFA should be performed to confirm the absence
of HIV-1 antibodies. Medical follow-up for further evaluation and testing may be required.
** It may be necessary to repeat a positive NAAT for confirmation
† If window period infection is suspected, refer to Acute HIV Infection Testing, Strategy 4
∞ If HIV-2 infection is suspected, refer to HIV-2 Testing, Strategy 5
Reference serology
Biorad HIV-1/2 plus O
N=342
P
165
N
Repeat in
duplicate
177
N
P
7
158
Western blot
I
P
77
41
N
40
77 reactive, 41 indeterminate, 224 non-reactive
Proposed Testing Strategies for Laboratory HIV
Testing Facilities
Strategy 3. HIV-1/2 Dual Immunoassay
A1 HIV-1/2 Immunoassay (e.g. EIA or CIA)
A1 (+)
A1 (-)
Negative for HIV-1 and
HIV-2 antibodies†
A1 (- -)
A2 HIV-1/2 immunoassay*
in duplicate
A2 (++ or + -)
Presumptive positive for HIV-1 or HIV2 antibodies; requires medical followup for further evaluation and testing
A2 (- -)
Repeat A1
in duplicate
A1 (++ or + -)
Inconclusive for HIV antibodies; request
plasma redraw for NAAT† Requires
medical follow-up for further evaluation
and testing
HIV-2 Testing; Strategy 5, if applicable
Dual EIA / WB
Abbott HIV-1/2 -Biorad HIV-1/2 plus O-WB
N=342
P
N
99
243
Biorad HIV-1/2 plus O
N
P
11
88
Western blot
I
P
76
19
N
4
76 reactive, 19 indeterminate, 247 non-reactive
EIA/RT
Biorad HIV-1/2 – Multispot HIV-1/2
N=342
P
N
165
HIV-2
HIV-1
78
177
Multi-spot
6
U
1
N
I
1
85 reactive, 1 invalid, 184 non-reactive, 72 inconclusive
79
EIA/RT
Biorad HIV-1/2 – Multispot HIV-1/2
N=342
P
N
165
HIV-2
HIV-1
78
184
Multi-spot
6
U
1
N
I
1
85 reactive, 1 invalid, 184 non-reactive, 72 inconclusive
72
EIA/RT
Abbott HIV-1/2 – Multispot HIV-1/2
N=342
P
N
99
HIV-2
HIV-1
73
243
Multi-spot
5
U
1
N
I
1
79 reactive, 1 invalid, 243 non-reactive, 19 inconclusive
19
Three test algorithm
Strategy 3/5
Biorad HIV-1/2 plus O
N=342
P
165
N
177
184
Abbott HIV-1/2
N
P
7
77
88
Biorad repeat X2
1
2
N
I
U
72
5
9
1
1
Multi-spot
1
6
2
1
N
63
I
0
70
U
0
84 reactive, 1 invalid, 1 undifferentiated, 184 non-reactive, 72 inconclusive
Performance comparisons
BR/AB/WB
REF
DATA
P
N
I
TOTAL
P
76
1
0
77
N
1
223
0
224
I
0
30
11
41
TOTAL
77
254
11
342
Sensitivity = 98.7%; Specificity = 99.6%
Algorithm summary data
Strategy 3
N=342
Algorithm
Pos
Neg
IND
INCa
INV
EIA/WB
77
224
41
0
0
AB*/BR
88
243
-
11
0
BR/MS*
85
184
-
72
1
AB/MS
79
243
-
19
1
BR/AB/MS 85
184
-
72
1
BR/AB/WB 77
254
11
0
0
•*All Abbott and Multi-spot data are single runs.
•a Inconclusive by Strategy 3
Algorithm summary data
N=342
Algorithm
Total Algorithm
Tests Cost ($)
Reagent Time
Cost /
T1
result
Time
T2
Time
T3
Total
time
EIA/WB
830
5507.11
16.10
2 hr
2hr
6hr
10
hr
AB/BR
562
1252.54
3.66
2 hr
2 hr
-
4 hr
BR/MS
646
3484.24
10.19
2 hr
30 min
-
2.5
hr
AB/MS
578
2534.00
7.41
2 hr
30 min
-
2.5
hr
BR/AB/MS
760
2824.66
8.26
2 hr
2 hr
30 min 4.5
hr
BR/AB/WB
760
3836.66
11.21
2 hr
2 hr
6 hr
10
hr
Reference serology
Biorad HIV-1/2 plus O
N=342
P
N
Repeat in
duplicate
165
177
N
P
7
158
Western blot
I
P
77
41
2
1
7
0
N
Multi-spot
N
1
34
2
40
N
2
1
87 reactive, 254 non-reactive, 1 invalid
36
25
20
15
10
5
OraQuick
WB positive
Uni-Gold
Vir HIV-1
Multi-Spot
GS rLav
Abbott
Reveal
WB Indeterminate
Procleix
GS HIV-1/2+O
Sequence of Positivity
0
Days before Western blot positivity
NAT> 3rd Generation EIA>2nd Generation EIA= Rapid>1st Generation EIA
Acknowledgements
Jane Feldman
Susan Wells
Michele Owen
Patrick Sprinkle